1. Am J Hypertens. 2011 Aug;24(8):843-53. doi: 10.1038/ajh.2011.115. Epub 2011 Jul

Reduced dietary salt for the prevention of cardiovascular disease: a
meta-analysis of randomized controlled trials (Cochrane review).

Taylor RS(1), Ashton KE, Moxham T, Hooper L, Ebrahim S.

Author information: 
(1)Peninsula College of Medicine and Dentistry, University of Exeter, Exeter, UK.

Comment in
    Am J Hypertens. 2011 Aug;24(8):854-6.
    Am J Hypertens. 2011 Aug;24(8):859-60.
    Am J Hypertens. 2012 Jan;25(1):18; author reply 20.
    Nat Rev Cardiol. 2011 Sep;8(9):479.
    Am J Hypertens. 2012 Jan;25(1):17; author reply 20.
    Am J Hypertens. 2012 Jan;25(1):19; author reply 20.
    Intern Emerg Med. 2012 Aug;7(4):371-3.

BACKGROUND: Although meta-analyses of randomized controlled trials (RCTs) of salt
reduction report a reduction in the level of blood pressure (BP), the effect of
reduced dietary salt on cardiovascular disease (CVD) events remains unclear.
METHODS: We searched for RCTs with follow-up of at least 6 months that compared
dietary salt reduction (restricted salt dietary intervention or advice to reduce 
salt intake) to control/no intervention in adults, and reported mortality or CVD 
morbidity data. Outcomes were pooled at end of trial or longest follow-up point.
RESULTS: Seven studies were identified: three in normotensives, two in
hypertensives, one in a mixed population of normo- and hypertensives and one in
heart failure. Salt reduction was associated with reductions in urinary salt
excretion of between 27 and 39 mmol/24 h and reductions in systolic BP between 1 
and 4 mm Hg. Relative risks (RRs) for all-cause mortality in normotensives
(longest follow-up-RR: 0.90, 95% confidence interval (CI): 0.58-1.40, 79 deaths) 
and hypertensives (longest follow-up RR 0.96, 0.83-1.11, 565 deaths) showed no
strong evidence of any effect of salt reduction CVD morbidity in people with
normal BP (longest follow-up: RR 0.71, 0.42-1.20, 200 events) and raised BP at
baseline (end of trial: RR 0.84, 0.57-1.23, 93 events) also showed no strong
evidence of benefit. Salt restriction increased the risk of all-cause mortality
in those with heart failure (end of trial RR 2.59, 1.04-6.44, 21 deaths).We found
no information on participant's health-related quality of life.
CONCLUSIONS: Despite collating more event data than previous systematic reviews
of RCTs (665 deaths in some 6,250 participants) there is still insufficient power
to exclude clinically important effects of reduced dietary salt on mortality or
CVD morbidity. Our estimates of benefits from dietary salt restriction are
consistent with the predicted small effects on clinical events attributable to
the small BP reduction achieved.

DOI: 10.1038/ajh.2011.115 
PMID: 21731062  [Indexed for MEDLINE]